While the heat, such as that evolved by a cost-effective, performance-optimized diesel engine, for example, can be very low on the cylinder crankshaft housing, this low heat in no way applies to “hot zones” such as in manifolds, turbochargers, catalytic converters, etc. As a result of the increasingly compact design of engines, components which are not thermally “compatible” are coming to be in ever closer proximity. It is then necessary to use shielding components, such as heat shields, to protect adjacent heat-sensitive assemblies, such as sensors, fuel lines, pressure cells, body parts, and so forth from heat-generating engine components. The situation is also exacerbated by the compact design in that the high packing density of the assemblies constricts the cooling air flow in the engine compartment. Noise abatement measures can also contribute to the problem. For example, under certain circumstances plastic floor plates having the function of reducing the level of sound emerging from the engine compartment to the roadway can produce effective insulation whereby heat is trapped in the engine compartment. Because of their high surface temperature in some phases, catalytic converters are among the heat sources which may necessitate the use of protective shield barriers. A typical example is that of design measures such as positioning the catalytic converter in the immediate vicinity of the manifold. This design principle performs the function of rapid heat-up of the catalytic converter to reduce emissions in the cold start phase, and shifts a major source of heat into the engine compartment where a considerable number of assemblies are crowded in a tight space. Another reason for the growing importance of shielding components, such as heat shields, is the trend toward use of thermoplastics. Light and economical materials with their exceptional moldability are rapidly becoming common in the engine compartment, but require special attention in view of ambient temperatures generated at the application site in connection with other heat-generating engine parts (“New Materials and Development Tools for Protection from Heat”, in MTZ 12/2001, Vol. 72, pp. 1044 et seq.).
DE 102 47 641 B3 discloses a shielding component, in particular in the form of a sound-damping structural component, as a component of a motor vehicle. In order to improve noise damping in the known shielding component, it has a shield body with a base edge as a shield component. The shield component can be fastened on the edge side by angular bracket legs within the engine compartment on stationary elements mounted in the compartment, and shields heat-generating engine components from heat-sensitive structural components.
The shield component in the disclosed design is arched in a U-shape in the central area, and is configured to be symmetrical for this purpose. The central U-shaped arched area undergoes transition on the edge side into edge areas of more pronounced curvature. The U-shaped arches on the two edge areas opposite each other are subsequently mounted as fastening means. The shield component has two layers of sheet metal, between which a sound-damping and/or heat-insulating layer extends. A border, in which the flanged edge of one cover layer covers the edge area of the other cover layer, is used for fastening the metal cover layers to each other. In order to reduce the weight, the shielding body may be made of aluminum or another light metal.
The disclosed solution is applied preferably to shield a coupling between a drive flange and a drive shaft from the sound of the body coming from the gearing and to exert a long-term effect through thermal radiation of an adjacent exhaust gas pipe.
Motor vehicle engines of identical design are currently used in a plurality of different vehicles. Based on the engine applications, however, increasingly modified add-on pieces are necessary, since their configuration is influenced for the most part by the overall installation situation (vehicle chassis). The structure and the configuration of the exhaust system, for example, are thus dependent on the type of engine, the output to be attained, and the exhaust gas classification to be achieved according to legal regulations. For an engine, this arrangement often yields several similar individual component systems which are dimensioned differently in terms of geometry, in particular in the form of exhaust gas systems with catalytic converters, as are likewise used at present in modern diesel engines in the form of so-called “soot particle burners.”
When the above described disclosed solutions are used for these applications, a heat shield component which differs in terms of geometry must often be developed and formed for each engine and/or its components such as exhaust systems. This development increases the production effort and consequently costs. Due to the resulting diversity of shield components, complexity is also increased in motor vehicle production lines, especially due to the associated additional effort with respect to parts management and parts storage. Furthermore, mixing up of parts may be possible, especially when they are to be replaced by new parts within the scope of subsequent maintenance. Fundamentally nothing changes in the pertinent problem if especially for large shielding components several individual heat shield components are connected to each other by conventional connection units such as screw joints or spring clamps.